Patent GB-1108799-A (GB)
Title: Roll film photographic camera
IPC: G03B19/04
Filed: 1965-09-22
Abstract: 1,108,799. Photographic cameras. FRANKE & HEIDECKE G. m. b. H. [trading as ROLLEIWERKE FRANKE & HEDDECKE]. Sept. 22, 1965 [Oct. 2, 1964], No. 40381/65. Heading G2A. The film winding mechanism of a roll film camera is adapted to accommodate a double length film, e. g.24 exposures instead of 12, by means of a manually operable cam disc 57 which temporarily uncouples counter mechanism 42, 43 from the film metering mechanism when half the film has been exposed while the counter wheel 42 returns almost to its zero position so that the latter is again prepared for the first winding-on step for the exposure of the second half of the film. Return of the wheel 42 to its zero position is prevented by engagement of stops 62, 64. Film F from a supply spool 2 is led to a take up spool 5, the film being driven by a film wind crank handle 9 through gearing 6, 7, 8. Closing the camera back rotates the lever 10 anti-clockwise through linkage 17-26 since a projection 20 on the camera back engages the lever 17, 19, thus bringing roller 3 into contact with the film and latching the ends 12, 13 of levers 10, 14. The link 24 also causes slide 31 to move downwards by means of linkage 28-30, thereby pivoting a lever 34 clockwise, thus disengaging a pinion 40 driven by the film metering wheel (not shown) through mechanism 38, 39 from the counter wheel 42 which is thereby free to take up its zero position. The apparatus is then in the position of Fig. 1a. The film is wound on until the connection F" of the film and the backing paper displaces the roller 3, hence the lever 10 moves clockwise, allowing the pawl 15 to release the lug 23 thus causing the slide 31 to rise bringing the pinion 40 into engagement with the counter wheel 42. Further advance of the film rotates the wheel 42, and when the first image frame is reached a lever 44 locks the disc 43 and the gear-wheel 8 by means of pawls 45, 46. Return movement of the handle 9 releases the pawls 45, 46. When e. g. 12 exposures have been effected, Fig. 2, (not shown), the stop 62 engages a lever 54 and drives it clockwise to the position of Fig. 3 (not shown), a projection 56 engaging a latch 50 to disengage it from a pawl 51 which is thus free to lock the film wind mechanism. Movement of lever 54 is limited by the projection 56 engaging the cam disc 57, so the counter mechanism is also locked. For preparing the counter mechanism for the second half of the film, the cam disc is rotated manually clockwise through 180. The slide member is first moved downwards by means of linkage 59, 60, 61 thereby disengaging the pinion 40 and wheel 42 to allow the wheel 42 to rotate clockwise from the position of Fig. 2 to that of Fig. 6 (not shown) where a stop 64 engages the stop 62 to prevent the wheel returning completely to its zero position. The slide member is then moved upwards allowing the pinion 40 and wheel 42 to re-engage. Rotation of the cam disc 57 also forces the projection 56 downwards swinging the lever 54 out of the path of the stop 62. The pawl 51 is disengaged from the disc 47 by release of the shutter, the film wind 9 is actuated and the film advanced to the counter position which corresponds to the 13th exposure. After the double length film has been run through, rotated of the wheel 42 is not prevented by the lever 54 so the crank 9 can be used to wind on the trailing end of the film since the pinion 40 is inoperative due to a gap in the teeth. Disengagement of the metering and counting mechanism to allow wind on of film may be effected at any time by turning the cam disc 57 through 90 Fig. 4, (not shown).